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e67b79850f
Linus observed that the pervasive passing of selinux_state pointers
introduced by me in commit aa8e712cee ("selinux: wrap global selinux
state") adds overhead and complexity without providing any
benefit. The original idea was to pave the way for SELinux namespaces
but those have not yet been implemented and there isn't currently
a concrete plan to do so. Remove the passing of the selinux_state
pointers, reverting to direct use of the single global selinux_state,
and likewise remove passing of child pointers like the selinux_avc.
The selinux_policy pointer remains as it is needed for atomic switching
of policies.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202303101057.mZ3Gv5fK-lkp@intel.com/
Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
121 lines
2.7 KiB
C
121 lines
2.7 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Copyright (C) 2021 Microsoft Corporation
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*
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* Author: Lakshmi Ramasubramanian (nramas@linux.microsoft.com)
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*
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* Measure critical data structures maintainted by SELinux
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* using IMA subsystem.
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*/
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#include <linux/vmalloc.h>
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#include <linux/ima.h>
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#include "security.h"
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#include "ima.h"
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/*
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* selinux_ima_collect_state - Read selinux configuration settings
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*
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* On success returns the configuration settings string.
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* On error, returns NULL.
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*/
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static char *selinux_ima_collect_state(void)
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{
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const char *on = "=1;", *off = "=0;";
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char *buf;
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int buf_len, len, i, rc;
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buf_len = strlen("initialized=0;enforcing=0;checkreqprot=0;") + 1;
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len = strlen(on);
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for (i = 0; i < __POLICYDB_CAP_MAX; i++)
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buf_len += strlen(selinux_policycap_names[i]) + len;
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buf = kzalloc(buf_len, GFP_KERNEL);
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if (!buf)
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return NULL;
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rc = strscpy(buf, "initialized", buf_len);
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WARN_ON(rc < 0);
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rc = strlcat(buf, selinux_initialized() ? on : off, buf_len);
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WARN_ON(rc >= buf_len);
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rc = strlcat(buf, "enforcing", buf_len);
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WARN_ON(rc >= buf_len);
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rc = strlcat(buf, enforcing_enabled() ? on : off, buf_len);
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WARN_ON(rc >= buf_len);
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rc = strlcat(buf, "checkreqprot", buf_len);
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WARN_ON(rc >= buf_len);
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rc = strlcat(buf, checkreqprot_get() ? on : off, buf_len);
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WARN_ON(rc >= buf_len);
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for (i = 0; i < __POLICYDB_CAP_MAX; i++) {
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rc = strlcat(buf, selinux_policycap_names[i], buf_len);
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WARN_ON(rc >= buf_len);
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rc = strlcat(buf, selinux_state.policycap[i] ? on : off,
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buf_len);
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WARN_ON(rc >= buf_len);
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}
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return buf;
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}
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/*
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* selinux_ima_measure_state_locked - Measure SELinux state and hash of policy
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*/
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void selinux_ima_measure_state_locked(void)
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{
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char *state_str = NULL;
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void *policy = NULL;
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size_t policy_len;
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int rc = 0;
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lockdep_assert_held(&selinux_state.policy_mutex);
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state_str = selinux_ima_collect_state();
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if (!state_str) {
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pr_err("SELinux: %s: failed to read state.\n", __func__);
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return;
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}
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ima_measure_critical_data("selinux", "selinux-state",
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state_str, strlen(state_str), false,
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NULL, 0);
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kfree(state_str);
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/*
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* Measure SELinux policy only after initialization is completed.
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*/
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if (!selinux_initialized())
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return;
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rc = security_read_state_kernel(&policy, &policy_len);
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if (rc) {
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pr_err("SELinux: %s: failed to read policy %d.\n", __func__, rc);
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return;
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}
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ima_measure_critical_data("selinux", "selinux-policy-hash",
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policy, policy_len, true,
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NULL, 0);
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vfree(policy);
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}
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/*
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* selinux_ima_measure_state - Measure SELinux state and hash of policy
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*/
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void selinux_ima_measure_state(void)
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{
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lockdep_assert_not_held(&selinux_state.policy_mutex);
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mutex_lock(&selinux_state.policy_mutex);
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selinux_ima_measure_state_locked();
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mutex_unlock(&selinux_state.policy_mutex);
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}
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